Two data sets
participants (\(n=106,817\))
screens (\(n=540,322\))
We have a list of 9 questions, roughly in order of importance.
632+756=1388 women with breast cancer (endpoint=1) have a detection mode that is either other or unknown.
The mode of detection is a key variable for women with cancer.
Can you think of any way to gain more information on the detec field from the cancer registry?
Removing 1388 out of 4545 women with breast cancer would lead to serious bias.
Among the 4545 cancers, 906 (20%) are coded as clinical.
This is more than expected; in the US, it is only about 20%.
While there are 4545 cancers, there are only 693+1545=2238 screens with BI-RADS of 4 or 5.
In Swiss practice, is it common for women with final BI-RADS finding of concl=3 to get a biopsy?
Is it a coincidence that many women were diagnosed as clinical right after their last screen?
Shouldn’t BI-RADS be missing (concl=9) when participants did not attend the screen (nopartreas=1,2,3)?
For instance, 1612 women were censored on May 14, 2018.